Influence of the addition of chlorhexidine diacetate on bond strength of a high-viscosity glass ionomer cement to sound and artificial caries-affected dentin

INTRODUCTION: The aim of adding chlorhexidine (CHX) to glass ionomer cements (GIC) is to improve their antibacterial property, but it may interfere with their bond to dentin. OBJECTIVE: To evaluate the influence of adding chlorhexidine diacetate at different concentrations to a high-viscosity GIC on its bond to sound and artificial caries-affected dentin. MATERIAL AND METHOD: Eighty human third molars were used, on which an area of dentin was exposed on the occlusal surface. Half of the specimens were kept sound and the other half were subjected to artificially induced caries. CHX was mixed with GIC powder at 0.5%, 1% and 2% (w/w). GIC without CHX was used as control. On each dentin surface a specimen measuring 1 mm in diameter and 1 mm high was made. The samples were kept at 37 °C and 100% humidity for 24 hours and subject to microshear testing. The results were analyzed using Kruskal-Wallis and Mann Whitney tests (α=0.05). RESULT: There was no significant difference between bond strength of sound and caries-affected dentin (p>0.05). For both substrate conditions, groups GIC, GIC+0.5% CHX and GIC+1% CHX showed statistically similar bond strength (p>0.05), and higher than that of GIC+2% CHX (p<0.025). Cohesive and mixed failures were predominant in all groups. CONCLUSION: The addition of 0.5% and 1% chlorhexidine did not result in negative changes in the bond strength of GIC to caries-affected and sound dentin.